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r nickel chromium.

Patented Get. 8, 1929 UNETE SATE FFICE CARL L. IPSEN, OF SCHENECTADY, NEW YORK, ASSIGNOR T0 GENERAL ELECTRIC COM- PANY, A CORPORATION OF NEW YORK FURNACE Application filed February 29, 1928. Serial No. 258,113.

My invention relates to furnaces, more particularly to electric furnaces of the resistance type and has for its object the provision of means for preventing scale or other waste material from damaging the resistors of the furnace.

In electric furnaces itis common to suspend the heating resistors from the side walls and also to provide resistors at the bottom of the furnace. These bottom resistors are sometimes located directly below suitable hearth plates on which the work to be heated is placed. The work, especially when consisting of small parts, is usually dragged in and out over the hearth plates and this dragging action often causes loose scale and other waste material lying on the plates to fall through the openings between them, and this scale has been found to lodge on the resistors and cause short circuits and the burning out of such resistors from its muflling effect.

In carrying out my invention I provide receptacle means at the junction of the hearth plate whereby this loose scale is collected and prevented from reaching the resistors.

For a more complete understanding of my invention reference should be had to the accompanying drawing in which Fig. 1 is a sectional elevation of a furnace embodying my invention; Fig. 2 is a sectional plan View taken on the line 22 of Fig. 1 but with part of the hearth plates broken away, and Fig. 3 is an elevation taken on the line 3-3 of Fig. 1 looking in the direction of the arrows.

Referring to the drawing a furnace is shown comprising outside walls 10 composed of a suitable heat insulating material and these walls 10 are lined with blocks 11 of a refractory heat resisting material. An opening 12 is provided through which the work may be placed in or taken out of the furnace. A refractory member 13 is located over the bottom wall 10 and contains grooves or channels 14 which serve as a containing means for a heating resistor 15. This resistor is formed of a plurality of parallel lengths of a ribbon of heat resisting metal such as The heating resistor 15 is mounted upon a plurality of elongated supporting and spacing members 16 and by means of these members 16 the convolutions of the resistor arekept in proper spaced relation. sister 15 through the terminals 17 which pass through the walls 10 and 11 andare suitably insulated therefrom. Mounted along the sides of the furnace are other resistors 18 and 19, which are suspended from hooks 20 attached in a well-known manner to the brick-work 11. Refractory spacing members 21 are also mounted in the walls 11 and are adapted to holdthe convolutions ,of theresistors 18 and 19 in proper spaced relation. Connections may be made to the side heating elements through terminals 22 and 23 passing through and suitably insulated from the walls 10 and 11. y 1 1 Located substantially at thecenter of the furnace and passing transversely thereof is a raised portion 24 which may be integral with and of the same material as the refractory material 13.- Placed upon and supported by the refractory member 24 is atrough or channel shaped pan 25. A groove 26 is cut in the rear wall 11 as shown in Figs. 1 and 2 and this groove acts as a supporting means for one end of hearth plate 27; The forward end of this hearth plate 27 is supported by the pan 25 and placed in end to end relation with this hearth plate isa second hearth plate 28, the forward end of which is supported on the walls 10 and 11 at the base of the opening 12. The hearth plates 27 and 28 may consist of channel shaped metallic members of some heat resisting metal. such as nickel chromium. As shown in Figs. 1 and 2 the bottom of the hearth plate 27 extends to the left and passes within the supporting groove 26. The hearth plates 27 and 28 are usually separated a short distance at their adjoining edges to allow for expansion and contraction of the plates. Vhen the material is being placed inor removed from the furnace it is usually dragged along on the surface of the hearth plates and any scale or other waste material which drops from the articles heated often falls between the adjacent edges of the plates 27 and 28 and this scale may Connections are made to the re-' eventually find its way to the heating resistors beneath the hearth plate. Scale or other waste matter collecting in this manner upon these resistors may cause a short circuit of a part thereof and may eventually lead to the burning out of one of the resistors, and it is for this purpose that the trough shaped member 25 is provided, as scale falling between the hearth plates will collect in this trough. By merely moving the plate 28 slightly toward the front of the furnace and lifting the forward end of the plate 27 the trough shaped scale pan 25 may be removed and cleaned. It can thus be seen that the pan member 25 performs two functions, namely, that of supporting the adjacent edges of the plates 27 and 28 and also providing means whereby scale or other waste material may be collected and thus prevented from causing damage to the heating resistors.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a furnace, heating means therefor, a hearth plate mounted over said heating means, and receptacle means forming a support for said plate for collecting waste ma terial falling from said hearth plate.

2. The combination with a. furnace, a plurality of hearthplates therefor arranged in abutting relation, and a supoprt for adjacent edges of said plates provided with a receptacle to collect waste material falling between said plates.

3. The combination in an electric furnace, of heating means therefor, hearth plates located above said heating means and a trough shaped member having its sides supporting adjacent edges of said plates so as to collect scale falling between the edges of said plates.

1. In an electric furnace, heating resistors therefor, hearth plates mounted over said resistors in close proximity thereto, and a removable metal support for said plates, said metal support comprising a trough shaped member, arranged with its sides extending upward to support said plates.

5. The combination in an electric furnace, of heating resistors therefor extending throughout the length of said furnace, a plurality of hearth plates mounted over said resistors, refractory supports for said plates lo cated at opposite ends of said furnace, and an elongated trough shaped support for said plates located between said end supports, said trough shaped support having its sides arranged to supportadjacentedges of said plates.

In witness whereof. I have hereunto set my hand this 28th day of February, 1928,

CARL L. IPSEN. 

